Distillation with aluminum chloride



Jul 8 1924. 1,501,014

A. MOD. McAFEE DISTILLATION WITH ALUM INUM CHLORIDE Filed March 29 1922 17 '11 um 1 Tom development of vapors of low boiling oils -atent edlluly 8,1924. r

Arman men.- MoAFEE, on roar ARTHUR,

* ram, or PITTSBURGH, PENNSYLVANIA, A CORPORATION or TEXAS.

, DISTILLATIQN WITH TEXAS, ASSIGNOR T GULF REFINING COM- ALUMINUM CHLORIDE.

s Application filed March 29, 1922. Serial No. 547,813.

To all whom it may concern: I Be it known that I, ALMER MoDUrFLE 'MCAFEE, a citizen of the United States,

' residing at Port Arthur, in the county of lo'lalumin-um chloride; and it comprises a process of distillin oil with aluminum chloride -wh'erein l dis'til ation is performed in a .column still havingfits base at'a tempera-- -tur e considerably higher than the tempera time at the top and provided with the usual heat economizer accessories used in column stills, the aluminum chloride being intro duced into the still at a mid-point in its height andexhausted chloride, with or' without substantial quantities of oil, being re- 'moved at or near the base, .vapors of low boiling oils produced being removed at the top and a feed of oil being introduced at or near such" top, the

*flow of oil so introduced'fbeing frequently substantially greater than the amount, catal'yzed in the column b the aluminum chloride with formation'o vapors, the excess of oil' in such cases being removed at the base together with exhausted, or nearly exhausted, aluminum chloride; and it fur- Y ther comprises certain apparatus useful in the performance of said process; all as more "fully; hereinafter set forth and as claimed.

',In certain methods now in. use for the production. of gasoline, or of gasoline and -kerosene, from higher boiling oils, a high boiling oil, as for example gas-oil, is placed in" a still, a small 'amount of aluminum chloride, often around 5. per cent, is added 'i and the mixture isheated to the temperature of free 'ebullitio'n under constant agitation,- Chemical action of the aluminum chloride on the high boiling oil takes place with going conversion.

. oil havingan initial nominal boiling point .of about 600 F.,. action often starts in at 475 and continues between 500 and-550 F. Practically all of the oil' can be converted into low boiling oils with very little loss. The operation results not only in the production of volatileoils but causes certam advantageous changes in the oil underduced are saturated in character, not tending to change or oxidize in storage and not requiring drastic treatment with sulfuric acidfor purification. Similarly, the oil in the still, if the operation be interrupted before it is completely converted into oils of lower boiling oint, and the alumi- The volatile oils pronum chloride remove is found to beof I improved 'quality. In another and prior Patent, No. 1,127,465 of February 9, 1915, I have described and claimed a process wherein improvement of oil is efiected in this way, av topped oil being distilled with aluminum chloride for a time to produce a certain amount of gasoline, or of gasoline and kerosene, the operationinterrupted and the residual oil" freed of aluminum chloride. This residual oil is of high grade and is particularly well adapted for use in making medicinal oil and lubricating oils of excel- .lentquality. Y In the manufacture of low boiling oils from higher boiling oils in such a conversion method, small, amounts of anhydrous aluminum chloride are-added to a body of oil in a still and the operation is conducted under, vigorous agitatlon. The aluminum chloride does not dissolve in the whole body of oil to makea uniform solution, but melts to form" a heavy liquid WhlCll is kept stirred up through, or emulsified in, the. rest of the oil by agitation. Aluminum chloride is -a volatile body and during the conversion a'certain amount of it vaporizes, either as such or in the'form of volatile combinations with oily hydrocarbons, and it is therefore usual to cool the vapors produced in the still down to about 350300 F to condense and returnvaporized aluminum chlo- I ride, prior to allowing the vapors of low 'boiling oils to go forward to the final or water 'cooledcondensers. As the operation goes on, the heavy oily liquid in the still changes in character and becomes more and more viscous and tarry. With this change a in character comes adiminution in activity.-

After a time, a sludge containing the spent chloride is removed from the still and sent to a recovery plant to regain active alum-i num chloride, fresh aluminum chloride be- .ing then charged into the still. 'As aluminum chloride combines with hydrocarbons, this loss of activity may be due to its combination with asphaltic or tarry hydrocarbons to form relatively inactive bodies.

Operating in the way described, the operation is, or may be, continuous as regards the oil, the still being supplied with fresh oil in amount equivalent to the amount removed in vapors. But the operation is not uniform, vapor production in the still at any given time depending somewhat on the age of the charge of aluminum chloride present. As regards the aluminum chloride, the operation is more or less discontinuous.

It is the object of the present invention to provide a method of and means for continuous operation; the operation being continuous not only as regards the oil but as regards the aluminum chloride, and the distillation being made uniform. To this end,

.I take advantage of certain of the phenomena previously noted. The operation may be so conducted as to give a total, or nearly total, conversion of the oil under treatment to oils of lower boiling point (gasoline or gasoline and kerosene), or it may be so conducted as to convert any desired proportion of the oil into oils of lowered boiling point and give residual oils of improved quality (as in the acknowledged prior patent).

As stated, in the still during the operation some of the aluminum chloride volatil-' izes and must be condensed and returned to the body of oil in the still. This returned material, formed from volatilized chloride is alwa s of high active nature; unlike that which finally occurs in the sludge, it is an energetic catalyst of the reactions here desired. In away, it may be said that of the aluminum chloride charged into the still part is in circulation between the vapor and liquid phases and retains its activity, while part occurs in heavy oily combinations, which finally become an inactive sludge. Actually, of course, there is no such sharp distinction, since some of the chloride of the heavy qily liquid vaporizes and some of the returned chloride goes into the sludge and all the chloride ultimately occurs in the sludge. In the present invention, I arrange conditions so as to keep the chloride as far as possible in the active, vaporizable form. To this end, I supply my chloride at an intermediate point in a flow of oil of progressively increasing temperature. In so doing, the heav oily combinations flow forward with t e oil while the vapors formed go backward against the flow. With one end of the system too cool to permit aluminum chloride vapors to escape and the other end hot enough to stri the sludge of volatilizable active ehlori e as far as possible, it will be seen that the chloride is, to a large extent, kept in the middle of the system and in active form.

' In practice, I use a device of the type of an ordinary column still; that is, a vertical column provided with the usual crossplates or devices whereby the downward progress of the oil is as a series of boiling or bubbling transverse pools, vapors formed in the still going upward through these pools; and I introduce fresh aluminum chloride at a midpoint. A tower with a packing of coke, shaped clay dividing devices, rings, etc, may be used in lieu of the column, but I regard the latter as best adapted for my purposes. The top of the system is maintained at a temperature low enough to ensure condensation of aluminum chloride vapors and the base of the still is maintained at a relatively high temperature, 600 F. or higher, with of course intermediate gradations of temperature at intermediate points. The aluminum chloride introduced at such an intermediate point is liquefied by the oil and tends, as a liquid, to flow forward and downward with the oil, but its vapors tend to pass upward in countercurrent against the flow of oil. In so doing, as will be seen, aluminum chloride, in so far as it is in active volatile form, is kept in the middle portion of the system. The exit temperature of the vapors from %he system is, as usual, kept around 300350 uch aluminum chloride as reaches the, base of the still is mainly in the inactive m0 .sludgy form and is there withdrawn, to-

gether with some, or much, of the oil. If theoperation is conducted with the object of producing improved residual oil, the amount of the oil passing out at the base of the column with the exhausted aluminum chloride may be considerable. If it be not, the base of the column may be kept at-a considerably higher temperature (such as is used in tar stills or coking stills) and in this event, the aluminum chloride reaching the base of the still is recovered; its combinations with tarry or asphaltic hydrocarbons are coked or broken up and the chloride liberated as vapor. This vapor ascends the column and takes part in the actions there going on.

The base of the column may be heated in any suitable way, as by placing it in a furnace chamber. This is convenient where high temperatures are required. In a modified form of my invention, heat-may be supplied by hot vapors, thereby accomplishing certain additional results.

As is well known, oils may be cracked or destructively distilled by exposure to high temperatures with production of a certain 1 amount of vapors of gasoline and kerosene.

densed oils are converted into lower boil-' ing oil vapors by the aluminum chloride and these vapors join those passing through boiling oils as are condensed from the vapors the bath.

As the vapors from a cracking still are usually at quite a high temperature, 700 F. or higher, they are well adapted for heating the still in the present process and they may be introduced into its base, passing upward.

in counterourrent against descending oil (and chloride).- In so doing, the vapors of low boiling oils are, as in the patent, saturated and improved and join those made in the still from the oil fed thereto. Such high may also be converted by the aluminum chloride, or, where the still is run to make a certain quantity of improved high boiling 7 oil, they may join this. The condensed hig boiling oils are improved in character by the aluminum chloride, their cracked nature being done away with. I

In the accompanying illustration I have shown, mainly in elevation with certain parts in central ver tical section, certain apparatus within the present nvention and useful in the performance of the stated process. I 1

In this showing, element 1 is a cohfmn still of the ordinary type; what is sometimes known as a beer still. It may be madeof iron or steel or other suitable metal. It is provided interiorly with the usual pool forming plates, here shown as perforated plates 2 with tubular connections 3 leading liquid from one plate to another; Around the base-of the still it is heated as shown'by fire chamber 4: provided with burners 5. All the heat, or some of it, may be supplied by leading in hot oilvapors by conduit 40'. which'may connect with a cracking still (not shown). Any other suitable method.

' vof heating to a high temperature may be used, that shown being merely illustrative.

The column is provided with a series of man- -holes 6, these permitting cleaning. There may be a'manhole opposite each plate to provide convenient access thereto. At the top,

,vapors pass through vapor conduit 7 pro-' vided with thermometer 8 to heat economizer 9. As shown, this is provided with tubes 10 passing between headers 11 and 12 forming a vapor space around the tubes. Any condensate formed in this vapor space passes out through trap outlet 12, which may be provided with valved draw-off 13 and which leads back to the still at a high point. Vapors not condensed inthe economizer pass forward through conduit 14 provided with thermometer 15 to a suitable condenser (not shown). Oil is sent to the still through pipe 16. As shown, this pipe is valved and directly connected, to the still at a middle point. There is another valved connection 17 leading oil into the base of the economizer to pass upward through the tubes therein and by conduit .18 to the still. Aluminum chloride is introduced into the still through valved pipe 19 at a midpoint, that is, a'point intermediate the relatively cold top and the relatively hot base. It is best introduced with oil as a magma. At the base of the still is valved outlet 20 through which alu minum chloride sludge and oil may be-withdrawn.

,The apparatus illustrated and described may be used in various specific ways under the present invention. Presuming that it is employed in the manufacture of gasoline (or of gasoline and kerosene) from gas oil, the

gas oil is introduced at 16 and a sufficient amount is sent throughthe economizer on its way to thestill via pipes 17 and 18 to hold the temperature of the vapors emerging through 14, as shown by thermometer 15,.

at about 300 F. Aluminum chloride is introduced at 19 and acts upon the oil flowing down through the still and entering through I pipes 16 and 18, either or both. Aluminum chloride vapors and light oil vapors rise in the still beyond the point of entry of 16 and 18 and are there fractionated, aluminum chloride being returned with downfiowing condensates. In part, the aluminum chloride passes down through'the still withthe oil from'18 entering progressively hotter distilling zones. The tendency is for the vapors to pass upward. As the aluminum chloride heavy oil combinations pass downward through the still, the aluminum chloride is constantly stripped therefrom, very'little in the active form remaining with the oil and reaching 20.. This gives an excellent utilization of aluminum chloride in the'st'ill. If

scribed in the acknowledged patent, the

operation is exactly the same, save that the flow of ,oil through the still is increased so as to have a substantial amount leaving-the layer, partly because of the catalytic action and partly by distillation, and this vaporization is aided by the vapors bubbling through the layer. These vapors include aluminum chloride coming from the hotter oil below; and in the vapor spaces between the transverse liquid layers, vapors of oil and of aluminum chloride have an opportunity to act on each other in the vapor phase.

The liquefied aluminum chloride traveling forward and downward with the oil is filmed out on the plates and a maximum opportunity for vaporization afi'orded. A sufiicient area of contact between the chloride and the oil is thus effected without the use of stirring mechanism, as is a common practice in the conversion of petroleum oils with aluminum chloride. In the column for a time vapors of aluminum chloride and hot liquid oil travel in countercurrent.

The present invention may be employed with other more or less volatile catalysts, such as aluminum bromid, tin tetrachloride, titanium chloride, etc.

What I claim is 1. The process of distilling oils with aluminum chloride which comprises establishing and maintaining a vertical downwardly flowing current of oil through a zone of progressively increasing temperature and supplying aluminum chloride thereto at a midpoint.

2. The process of distilling oils with aluminum chloride which comprises establishing and maintaining a vertical downwardly flowing current of oil through a zone of progressively increasing temperature, the

emme top of said zone being at a temperature sufficiently low to hold back vapors of aluminum chloride and the base at a temperature high enough to cause free vaporization u of aluminum chloride, and supplying aluminum chloride to said current at a midpoint.

3. In the distillation of oils with alu-' 4.. In the distillation of oils with anminum chloride, the process which com-v prises leading oil downward through a column still with its base at a temperature of 600 F.- or higher and its vapor-outlet not above 350 F. and charging aluminum chloride into the downflowing oil at a midpoint.

In the catalysis of oils with aluminum chloride, the process which comprises passing aluminum chloride vapors upwardly through successive transverse layers of downwardly flowing hot oil.

6. In the catalyzed distillation of oil with aluminum chloride, the process which comprises passing liquid oil and aluminum chloride vapors in contact in countercurrent, in a heated zone with temperatures progressively increasing in the direction of the flow of oil'and supplying oil and aluminum chloride to said zone at a midpoint, the amount of oil so supplied being greater than will be catalyzed to lower boiling oils by the action of said chloride.

7. In the distillation of oils with aluminum chloride, the process which comprises leading oil downward through a column still with its base at a high temperature and its vapor outlet not above 350 F charging aluminum chloride into the downflowing oil at a midpoint and supplying oil vapors at the base to afford heat.

In testimony whereof, I have hereunto affixed my signature.

ALMEl MOD. MGAFEE. 

